can we do manual focus by manually rotating the front element instead of using the focus ring? does it work? I think it will, and then use the focus ring to fine tune. but will it damage the internals? any thoughts anyone...

First it's focus by wire, so there's no interconnection to the mechanicals.

Second, the autofocus is quite good...I've never found the need to manually focus after autofocusing.

And just to let you know how MF works, if you select AF+MF you have to have the shutter release half-pressed to do manual focusing. If you are in MF mode, you can use MF without pressing the shutter release.

the only time that I wanted to do MF was when I went to a tiger show, because the AF will always focus on the fence. I did a lot of manual focus-ed shots, but 90% of them were out of focus (I only blame myself for that). Here is one that I managed to get it right.

Set the AF to only use the centre focus point (personally I always have the other two focus points turned off). Then set the centre point through an opening of the fence. And to get rid of the fence is open up your aperture (f-stop) as much as possible (even at the cost of telephoto, you can do a crop in later on the computer).